My mason has a mind of his own. I gave him the Pompeii oven plans MONTHS ago an have talked to him about what I want (a neopolitan low-dome) but he pretty much works out the design in his own head and does what he wants. So far this has been okay. He really is a talented man. He started the dome this week. He's just about to the point where he'll fill the oven with sand to finish off the dome. (He decided he didn't want to do the extreme neopolitan, so we agreed on a hybrid.) Last night I went out and measured the cooking floor. It's barely 40" and it was supposed to be 42!

In and of itself, this is not an oven-killing thing. But since he has obviously not followed the instructions, I'm concerned he'll do something else that will result in a poorly-functioning oven. He's a very stubborn man.

My question is: Can I cure the oven once the dome is complete and then test it to see how it works? Should I install the insulfrax blanket first? Before curing or just before full firing?

There's always a chance the oven will work perfectly. But if it doesn't, I don't want to have to tear down the outer wall, roof, etc to rebuild it. I can live with just tearing down the oven and starting on the base again. If testing the oven at this stage (assuming a full cure as outlined in the plans) isn't possible, I will tear it apart and start over from the base.

He's just about to the point where he'll fill the oven with sand to finish off the dome.

Just a point, I think this sentence means that he is using the sand as a form to build the last courses. There are traditions of INSULATING the oven with sand. Just make sure he's using real insulating materials, not cheap sand around your dome.

For the record, I cured mine before insulating, this helped me identify and fill cracks.

I have read the arguments about insulating before and how that may cause less thermal shock. I don't see how that could be true. If anything it would mean that the oven gets hotter when insulated, therefore more thermal shock...call me a doubter...
Anyway, I would cure it first and patch the inevitable cracks, then insulate and build the enclosure...

I have read the arguments about insulating before and how that may cause less thermal shock. I don't see how that could be true. If anything it would mean that the oven gets hotter when insulated, therefore more thermal shock...call me a doubter...
Drake

Good point.

I hadn't though about it that way.

If the blanket is on, I guess it would get hotter faster, but wouldn't it cool more slowly? Maybe heat it up with no blanket, then throw one on for cooling
down.

Got to agree with Drake. Curing the chamber first exposes weaknesses that could potentially damage the insulation layer and provides the opportunity to fix them.
In addition when curing the oven it moves in all directions more radically than it does once cured.

May or may not be a big difference with firebricks, but the thermal stress is greater without insulation, no doubt about that. The stress is greater because the temperature gradient across the brick or dome is greater and that gradient is what produces the stress.

Again, while it may or may not make a huge difference, I believe it is better to fire/cure after at least a blanket of insulation. That is what I did. If you have cracks or want to inspect it is no big deal to pull back the blanket. I am still 100% crack free.

[QUOTE=wlively;16429] The stress is greater because the temperature gradient across the brick or dome is greater and that gradient is what produces the stress.
QUOTE]

Not disputing this theory in any way I just want to understand more. Did you arrive at this with the fact that the insulation is holding the heat in mind? Meaning, since the insulation is, for lack of a better description, distributing..(actually encapsulating may be a better term) the captured heat its causing the dome to heat more evenly? Thus reducing stress.

No part of this website or content thereof may be reproduced, distributed or transmitted in any form or by any means, nor may any part of this website be stored in a database or other electronic retrieval system, or any other website, without the prior written permission of Forno Bravo.